build: update sphinx tool

Use the improved version from the ndn-cxx repository

Refs: #5298
Change-Id: I681f38faa0078a67089b6a9c22eb56572a1c2940
diff --git a/wscript b/wscript
index c5cab7f..50c8cf8 100644
--- a/wscript
+++ b/wscript
@@ -1,6 +1,6 @@
 # -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 """
-Copyright (c) 2014-2023,  The University of Memphis,
+Copyright (c) 2014-2024,  The University of Memphis,
                           Regents of the University of California,
                           Arizona Board of Regents.
 
@@ -31,7 +31,7 @@
     opt.load(['compiler_cxx', 'gnu_dirs'])
     opt.load(['default-compiler-flags',
               'coverage', 'sanitizers', 'boost',
-              'doxygen', 'sphinx_build'],
+              'doxygen', 'sphinx'],
              tooldir=['.waf-tools'])
 
     optgrp = opt.add_option_group('NLSR Options')
@@ -57,7 +57,7 @@
 def configure(conf):
     conf.load(['compiler_cxx', 'gnu_dirs',
                'default-compiler-flags', 'boost',
-               'doxygen', 'sphinx_build'])
+               'doxygen', 'sphinx'])
 
     conf.env.WITH_TESTS = conf.options.with_tests